1. Field of the Invention
This invention relates to a power control apparatus.
2. Related Background Art
Many fires are caused by faulty electrical wiring or by electrical appliances malfunctioning or overheating. Many fires are also caused by overheating liquids and solids (such as food and drink), which are being heated or cooked using a cooking appliance. Generally, before a fire starts, the source of the fire normally emits smoke. This smoke can be detected by a fire alarm system or smoke detector(s) to warn the occupants of a building that smoke has been detected. The occupants may take remedial action upon hearing the alarm to address the cause of smoke before a fire starts, for example by switching off the appliance or unplugging the electrical appliance or by removing the source of heat from a liquid or solid which is being heated or cooked.
Known fire alarm systems save property and many lives. A great deal of properties are still needlessly damaged or lost to fire. Many people are also injured or killed. A large number of fires either occur because the building is empty and a smouldering fire has the opportunity to take hold, or because the occupant(s) simply leave the building when an alarm occurs. Sometimes occupants are incapable of taking action at the time because, for example, they are asleep, overcome with fumes, too young, panicked, trapped, disabled or affected by drugs or alcohol. In this manner, a great deal of properties are needlessly damaged or lost to fire. Many people are also injured or killed. Some people are injured or killed attempting to stop the outbreak or spread of fire.
Most fires are extinguished using water and a problem with this is that it can be dangerous to extinguish fires using water, since water is a conductor of electricity, thus Firemen run the risk of electrocution.
AU2003200895 discloses a fire prevention apparatus which attempts to alleviate the above-mentioned problems and which comprises a smoke sensor having an output which is connected to a switch of the apparatus. The switch is wired in series with the mains supply which feeds electrical appliances. In use, an electromagnetic coil keeps the switch contacts closed to allow the appliances to function in the usual manner.
Upon detection of fire, the smoke sensor sends a signal to the switch to energise or de-energise the coil the result of which is that the switch contacts open, such that the electrical appliances are isolated from the supply. A disadvantage of the above-mentioned apparatus is that the switch needs to have contacts of a suitably high current rating to handle the current drawn by the appliances. Furthermore, the switching circuit is expensive in construction and occupies a physical space. Also, the apparatus is costly to run since the electromagnetic coil is normally energised. There is also a risk that the coil could overheat and start a fire.
I have now devised a power control apparatus which alleviates the above-mentioned problems.